- add more details on custom checkboxes and radios for how we handle the states and how the css works
- create a disabled custom checkboxes and radios example

- Less nesting with more specific classes
- New class names for most elements to avoid unnecessary and potentially confusing shorthand
- Require new class and markup for the description (though it's only necessary for disable states, it's now part of the entire component's markup for all states just in case)
- Change up colors and variables for regular and disabled states

v4: font-weight: normal on labels

Grunt: Extract lint-docs-css task

[skip sauce]

v4: Docs Sass linting

Docs: accessibility fix-up of collapsible content navbar, change site-wide main navbar

remove `<div class="bd-sidebar">`

Docs: add note and advice about .disabled and keyboard focus

Remove .dl-horizontal; it's redundant to the grid system

Docs: tweaks to content code

Add tether as bower dependency

* https://bugs.webkit.org/show_bug.cgi?id=152637
* http://openradar.appspot.com/24030853

[ci skip]

[ci skip]

[ci skip]

Refs #18728
[ci skip]

Fixed NuGet link and bugs in MyGet script

Docs: update browser support info

Add pointer-events:none to disabled pagination/pager links

Add max-width to file browser; fixes #18651

As per our browser compat policy, we only claim support for latest
versions of Opera on desktop. Current Opera is version 34. From testing, IE11 does support `pointer-events:none` just fine now.

as currently this was missed out (compared to disabled `a.btn`)